They say that the car went 100 miles on four ounce of water. But there always appears to be some sort of electricity involved somewhere. Is the system fully contained? Is there only water and NOTHING else?

I'm pretty sure James Randi has written about this exact thing before. I'll try and dig around on his site when I get home and find the article he wrote. I'm sure I can find some other fellow skeptics who have commented on this as well.

100 miles on 4 ounces of water? that i do NOT believe. If he's done this, then the world is about to SERIOUSLY change for the better. He should be able to get plenty of funding from some environmental group, unless you believe in conspiracy theories and how Big Oil is never going to let this happen.

my guess is that the guy is either a con-artist, or seriously delusional in his grasp of physics.

There already exist hydrogen-powered vehicles. Their method of operation is to burn the hydrogen, producing water plus energy. So if it's also possible to produce energy by splitting water into hydrogen plus oxygen, you could make a perpetual-motion machine.

But you can't make a perpetual-motion machine. And hydrogen-powered vehicles exist. Therefore these water-powered vehicles can't exist.

James Randi first commented on this in May of 2006. I would think that if this was legit, we'd have heard about it from a more legitimate news source than YouTube. Maybe Scientific America or Discover would have run a story on it by now.